The present invention relates to pistons and, in particular, to a molded piston.
Piston-cylinder assemblies are used in a wide array of industrial applications. Although high-speed and high-temperature applications often require metal pistons, plastic composites are preferred in lighter duty applications such as pneumatic actuators; however, prior art plastic composite pistons have had many problems.
Generally, in the prior art, plastic pistons are molded by bonding a polymeric compound to a metal plate; however, the bonds between the polymer and the metal plate tend to fail during operation of these pistons, making them impractical for most uses.
In the prior art, rubber seals are usually installed on the piston to provide a seal against the cylinder wall. These seals create substantial friction and tend to fail rapidly, particularly when contaminants are present in the cylinder.
Further problems common in prior art piston-cylinder assemblies are the noise and vibrations produced by the impact of the piston against the cylinder head. Also, the repeated shock of the impact of the piston against the cylinder head often causes failure of associated components of the assembly. Prior art devices have attempted to minimize these problems by using an air cushion or similar devices, but these methods often require expensive additional equipment and create additional problems.